Fiber sheet and its manufacture



March 27, 1934. V E. H. Hussey 1,952208 FIBER SHEET AND ITS MANUFACTUREI Filed May 18, 1931 is; Q

Patented4 Mar-. 27,` 1934 man SHEET AND rrs MANUFACTURE Erwin H. Hussey,Springeld, Ohio Application May 18, 1931, Serial No. 538,088

9,Claims. (Cl. 154-23) This invention relates to the manufacture ofthick brous sheets and, among other objects, aims to provide an eicientand economical process for making thick brous sheets in which the 5 bersare interconnected without impairing the insulating qualities of the4sheet. U

'151e nature of the invention may be readily understood by reference toone yillustrative embodiment thereof shown in the accompanying ldrawing. f

In said drawing, A

`If'ig. 1 is a more or less diagrammatic view showing an elevation ofthe devices for initially forming the sheet; and

'15 Fig. 2 is a similar elevation of apparatus forming a continuationFig. 1.

In the illustrative process, the'mass of bers are interconnected by anadhesive, as distin- 90 guished from connecting by felting the berstogether, in order to provide a sheet cf looser character than a feltedsheet wherein compression or an intimate association of bers isnecessary to effect a felting .and interlocking of the '25 bers. Thelatter form of sheet is of course much denserv in character and does notpossess the insulating characteristics of the more porous sheet.

To provide a porous or loose sheet of this char- 80 acter, treatmentswhich tend to compact the bers are avoided. To this end, the formationof the sheet by the use of a water pulp is avoided because in the latterprocess thedraining of the water away from the pulp layer inevitablyproduces a rather cle and undesirable (from the insulating standpoint)compacting of the bers. Instead, the bers are used without a watervehicle and are interconnected by the use of an adhesive which isapplied to the bers. In the 4 present instance, the adhesive is appliedand excess adhesive removed, befcreany sheet forming operations, inorder to avoid the .disturbance of the loose layer of bers by anysubsequent operation of this character,

To secure a uniformly thick layer of bers, the initially deposited layerof ber is repeatedly levelled by removal of bers forming high spots inthe layer, and then the levelled layer is picked apart and uniformlyredeposited in another layer. The successive levelin'gs andredepositingoperations eventually produce a brous layer quite as looseas the original layer. and in which the bers are uniformly distributedand which is of uniform thickness. The sheet is then dried to set theadhesive and preferably very slightly comof the apparatus. shown indevice 10.

Apressed in order to hold ldown projecting bits of ber and provide asmoother surface.

In the drawing is illustrated diagrammatically one procedure forperforming the inventive process. The ber, which may be of vegetable,wood or mineralcharacter or a mixture of these, is employed in dry form,that is, with only about 10 to 15% moisture, which is approximately thenatural moisturev content of the ber. It is first subjected to a coarseshredding operation in a hammer machine or hog, diagrammaticallyindicated at 10, and then later to a ne shredding operation in apparatussuch as a single disk brator which may be purchased on the market.

AA iine shredding device is here indicated at 11 receiving the coarseshredded bers from the 'Ihe nely shredded bers are then screened toremove dirt and so-called nes and are then delivered to a device,represented at 12, for mixing the ber with an appropriate adhesive.' Forthis purpose, a mixing device, such as is used for mixing cattle feedwith molasses, may advantageously beemployed. Mixers of this charactermay be purchased on the open market. A great variety of.adhesives may beused, such as starch and dextrine adhesives, -glue or rosin, or for towater and weather-proof the bers, a high melting point asphalt may beemployed. Adhesive somewhat in excess of that necessary to coat the bersis introduced`into the rnixer and the excess adhesive is later expressedfrom the bers by the subsequent operations, thereby insuring an adequatecoating of the bers. The excess adhesive may conveniently be expressedfrom the bers by delivering the mass of bersv from the adhesive mixer 12to an enclosed screw conveyor 13 which carries the mass of ber along andforces it through a conned passage 14 not provided with any screwconveyor. The friction of the passage coupled with the action of'theconveyor in attempting to advance the mass of .bers places them undersubstantial compression and expresses the excess adhesive which may passthrough the perforations 15 in the walls of the passage 14 from which itis collected in a receptacle 16 for re-use. The compressed ber is thendelivered to agitating apparatus, indicated diagrammatieally at l?,which generally loosens the compressed vbers and delivers the loosenedmass of adhesive coated bers to a. distributing device 18 in the form ofa worm conveyor having an inclined delivery edge 19. This device withits inclined delivery edge serves some purposes, such as where it isdesired fully lio to deliver the fiber fairly uniformly across a beltlevelled by the brush roll 27, as above described, conveyor 20 (shown inFig. l as `travelling perafter which, the sheet is subjected, asaforesaid, to pendicularly to the plane ofthe drawing and in drying andother subsequent operations. Fig. 2 as travelling parallel therewith.The layer Obviously, the invention is not limited to the of fibersdeposited on the belt 20, while fairly details of the illustrativeembodiment herein iluniform as regards to the rate of feed anddislustrated and described. Moreover, it is not intribution across thesheet, is not uniform in dispensable that all features of the inventionbe thickness, as indicated in Fig. 2. used conjointly, since variousfeatures may ad- To improve the uniformity oi the sheet, thevantageously be employed in different combinalayer of fibers is pickedapart by a rotating picker tions and subf-combinations. roll 21 whichserves not only to loosen the fibers Having described my invention, Iclaim: but to distribute inequalities in the supply of l. The method ofmaking sheet maerial of the fiber. From the picker roll the fibers fallupon character described which is characterized by a continuouslytravelling conveyor 22, the layer covering a mass of fiber with a liquidadhesive so on this conveyor being somewhat more uniforml asto coat theindividual bers, agitating'said mass both in character and thicknessthan on the conto loosen and separate the coated bers and deveyor 20.inequalities in the thickness of the positing the same in a sheet likelayer in loose sheet lare removed by a rotating brush roll 253 andunfelted condition, passing said shee'; under a whose direction oftravel is opposite that of the rotary levelling brush to remove highspots in said conveyor 22 and which serves to remove the fiber sheet,and then drying said sheet to permit the in the high spots on the sheetand throw it back adhesive to set. toward the point of delivery where itis moreor 2. The method of making sheet material of the less uniformlyscattered in the layer of fiber. character described which ischaracterized by A cleaning brush roll 24 rotating in a directionmechanically agitating a mass of fibers coated opposed to the roll 23,serves to remove fiber adwith liquid adhesive to loosen and separatethem, hering to the brush roll. The levelled layer of depositing them inloose condition in a layer, and fibers is then advanced to anotherpicker roll 25 picking said layer apart and redistributing the whichserves again to loosen the layer of fibers fiber in another layer tosecure more even `disand further to redistribute any inequalities intribution of the ber in the layer and to produce distribution of berthroughout the layer and to a more uniform layer thickness without theuse deposit the fibers upon another continuously of substantialpressure.

travelled conveyor 26. The slight inequalities in 3. The method ofmaking thick fibrous sheet thieknessin this layer are removed by anotherinsulating material which is characterized by rotating brush roll 27similar to the roll 23 leavmixing disintegrated fiber with an adhesive,forcing a levelled loose fibrous layer 28 which is not ing the massthrough a confined passage to comonly uniform in thickness, but in whichthe fibers press it and discharge excess adhesive, loosening areuniformly distributed. If desiredthe thickthe fibrous mass anddepositing itin a. layer on a ness of the fibrous sheet may be varied byregus continuously travelling carrier, continuously tearlat'ing therelative speeds between conveyors 20 ing said layer .apart to loosen theiiber and reand 22 and between 22 and 26. depositing it in a layer on acontinuously travelvA cleaning brush roll 29, similar to the roll 24,ling carrier to improve the uniformity of the is provided for the brushroll 2'?. 'I'he fibrous layer, passing said layer under a rotatingleveller layer 28 is then Carried by the eOnVeyOi 26 01' to remove thebers in the high spots in said layer,

successive conveyors which are advantageously and then drying the sheet.

supported level by theusual rolls e0 through the 4. The method of makingthick sheet insulating 12o necessary drying Operations. duringwhich'thev material 'which is characterized by mechanically adhesivesets. Preferably, the sheet is given an agitating a mass of fiberscoated with a liquid initial drying Operatien sumeient to permit it toadhesive to loosen and separate them, depositing be cut transverselyinto sections for convenient them in loose condition to form a layerwithout handling in the Cutting Operations in which the the use ofcompression, feeding said layer to a sheet is cut into desiredcommercial sizes. Preferpicker roll which pulls the ber apart andconably, during the `.drying Operations or until the tinuouslydischarges it in a layer upon a continuadhesive has Set;y slightPressure bym-eens 0f a ously travelling carrier, and then passing theslnooth belt 0r Otherwise is applied t0 the surface .layer under a.rotating brush roll to remove the of the sheet to hold down anyresilient ilber ends fiber in high spots on said layer. v whichmay-project above the true surface 0f the 5.l The method of making thicksheet insmeting layer. thus providing e fibrous sheet which has materialwhich is characterized by meeha'nieeuy relatively smooth surface.Thisbelt or other comagit-,ating a mass of fibers coated with a, nquidDressing means may alsO serve t0 gauge the Sheet adhesive to loosenandseparate them, delivering to standard or accurate thickness- .l saidfibers, in loose condition, to a continuously It will be understood fromthe foregoing that travelling carrier and allowing them to form a thesheet is Very Porous and loose in ehslseter. loose unfelted j layer;repeatedly mechanically and that the fibers are held together orinterconseparating the fibers in the. layer 'and then denested by theadhesive With sumeient rlnness t0 positing them again upon a travellingcarrier; 1 preserve the integrity of 'the sheet.- and, following eachdepositof the bers in layer 140 If it be desired to provide a sheet inwhich the form, passing the same under a rotating brush surface isformed of flner fibers. this can be advanroll to level the sheet byremoving the fiber in the tageously don'e by rst depositing uponthe nalhigh spots in the layer.

conveyor 26; athin layer of lneflber in the man- 6. 'I'he method of.making thick porous fibrous nerI previously described. Then a, layer ofcoarse. sheets which is characterized by mechanically ber is depositeduPOn the ne ber lsyiel The agitating a mass of'fibers thoroughly coatedwith coarse fiber layer may be levelled or not, dependliquid adhesive toloosen and separate-them, reing upon the character of its surface andthen, if peatedly depositing said iber in loose condition desired, a toplayer of ne ber maybe deposited on a continuously travelling carrierfollowed by on the layerlof coarse fiber and the whole sheet a repeatedlevelling of the sheet by removing the iiber in the high spots in saidlayer, thereby fo ing a. loose sheet-like layer of substantially uniformthickness and condition, and then drying said sheet and permitting theadhesive to set.

7. The method of making thick, loose brous sheets of the characterdescribed which is characterized by covering a mass of-fiber with aliquid with liquid adhesive to loosen and separate them, depositing themin loose condition to form a layer without the use of substantialcompression, levelling said layer by removing the iiber forming highspots in said layer, and then drying said layer to permit the adhesiveto set.

9. The method oi' making thick fibrous sheet material of the characterdescribed which is characterized by covering a mass of ber with a liquidadhesive so as thoroughly to coat the individual bers, separating theexcess adhesive, mechanically agitating the coated fibers to separateand loosen them, depositing them in'loose condition in the form of athick layer in substantially unfelted condition, and then drying saidlayer to permit the adhesive to set.

ERWIN H. HUSSEY.

